Whole erythrocytes, native ghosts, modified ghosts, extracted proteins and extracted lipids will be studied using scanning calorimetry, various spectroscopic methods, chromatographic methods, and by measuring anion flux. Under certain conditions, the erythrocyte membrane can be seen to undergo five structural transitions over the temperature range 45 degrees to 75 degrees C. The transitions are irreversible and only two of them (A and D) involve measurable changes in CD. The involvement of integral membrane protein is indicated by thermal gel analysis, with the important protein, band 3, participating in the B2 transition and bands 4.1 and 4.2 involved in the B1 transition. Only the C transition remains on extensively-proteolyzed ghosts and it is this same transition which is most easily lost by treatment with various phospholipases or by lipid extracting procedures. The C transition is also drastically altered by specific covalent inhibitors of anion transport while the B2 transition interacts with many noncovalent inhibitors. Future work will attempt to determine the specific phospholipids which might be involved in the C transition and to determine if this transition is a gel-to-liquid-crystal melting phenomenon. By selective modification of ghosts, the specific roles of the B2 region and C region in anion transport will be probed. Various studies of extracted band 3 in detergent solutions and in reconstituted vesicles will be conducted, in an effort to better understand its behavior on the membrane. A search for similar structural regions in other membranes with anion transport systems will be started.